1. Field of the Invention
This invention relates to a circuit breaker of the current limiting type and, more particularly, it pertains to a two level current limiting circuit interrupter.
2. Description of the Prior Art
In most current limiting devices the load side of the current limiter has a lower energy withstand (I.sup.2 t) and peak let-through current capability than the main or supply side of the equipment. For example, the 400 ampere current limiter will limit a 170 KA fault to approximately 46 KA at 600 volts. The current limiter can absorb this level of peak let-through current and I.sup.2 t several times. However, it is desirable to further reduce let-through current so that smaller breakers and equipment downstream can be protected. The overall problem has been to reduce the peak let through current and I.sup.2 t to an acceptable level on the main or supply side and to reduce it to a much lower level on the low side of the circuit breaker.